Commit Graph

22 Commits

Author SHA1 Message Date
wangpc 8def89b5dc [RISCV] Set CostPerUse to 1 iff RVC is enabled
After D86836, we can define multiple cost values for
different cost models. So here we set CostPerUse to
1 iff RVC is enabled to avoid potential impact on RA.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D117741
2022-01-21 14:44:26 +08:00
Haocong.Lu bd653f6406 [RISCV] Use shift for zero extension when Zbb and Zbp are not enabled
Now AND is used for zero extension when both Zbb and Zbp are not enabled.
It may be better to use shift operation if the trailing ones mask exceeds simm12.

This patch optimzes LUI+ADDI+AND to SLLI+SRLI.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D116720
2022-01-11 02:37:03 +00:00
Craig Topper b271184f07 [RISCV] Use FP ABI on some of the FP tests to reduce the number of CHECK lines. NFC
These tests are interested in the FP instructions being used, not
the conversions needed to pass the arguments/returns in GPRs.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D116869
2022-01-10 09:08:29 -08:00
Craig Topper 0ec5f1e64f [RISCV] Reduce duplicate FP test cases.
-Remove feq, fle, flt tests from *-arith.ll in favor of *-fcmp.ll which tests all predicates.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D113703
2021-12-09 08:33:38 -08:00
Hsiangkai Wang 137d3474ca [RISCV] Reverse the order of loading/storing callee-saved registers.
Currently, we restore the return address register as the last restoring
instruction in the epilog. The next instruction is `ret` usually. It is
a use of return address register. In some microarchitectures, there is
load-to-use data hazard. To avoid the load-to-use data hazard, we could
separate the load instruction from its use as far as possible. In this
patch, we reverse the order of restoring callee-saved registers to
increase the distance of `load ra` and `ret` in the epilog.

Differential Revision: https://reviews.llvm.org/D113967
2021-11-22 23:02:11 +08:00
wangpc af0ecfccae [RISCV] Generate pseudo instruction li
Add an alias of `addi [x], zero, imm` to generate pseudo
instruction li, which makes assembly mush more readable.
For existed tests, users can update them by running script
`llvm/utils/update_llc_test_checks.py`.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D112692
2021-11-22 14:01:37 +08:00
Craig Topper eb44f3fc58 [RISCV] Add rv32i/rv64i command lines to some floating point tests. NFC
This improves our coverage of soft float libcalls lowering.

Remove most of the test cases from rv64i-single-softfloat.ll. They
were duplicated in the test files that now test softflow. Only
a couple test cases for constrained FP remain. Those should be
removed when we start supporting constrained FP.

This is follow up from D113528.
2021-11-11 10:56:27 -08:00
Craig Topper ed95cafbc5 [RISCV] Add an implementation of isFMAFasterThanFMulAndFAdd
Start with an assumption that FMA is faster than Fmul+FAdd. If thats not true
on some particular implementation we can add a tuning parameter in the future.

I've update the fmuladd test cases and added new test cases for fast math flag
based contraction.

Differential Revision: https://reviews.llvm.org/D91987
2020-11-25 15:07:34 -08:00
Craig Topper 4252f7773a [SelectionDAG][ARM][AArch64][Hexagon][RISCV][X86] Add SDNPCommutative to fma and fmad nodes in tablegen. Remove explicit commuted patterns from targets.
X86 was already specially marking fma as commutable which allowed
tablegen to autogenerate commuted patterns. This moves it to the target
independent definition and fix up the targets to remove now
unneeded patterns.

Unfortunately, the tests change because the commuted version of
the patterns are generating operands in a different than the
explicit patterns.

Differential Revision: https://reviews.llvm.org/D91842
2020-11-23 10:09:20 -08:00
Craig Topper defe11866a [RISCV] Add isel patterns for fnmadd/fnmsub with an fneg on the second operand instead of the first.
The multiply part of FMA is commutable, but TargetSelectionDAG.td
doesn't have it marked as commutable so tablegen won't automatically
create the additional patterns.

So manually add commuted patterns.
2020-11-05 14:00:25 -08:00
Craig Topper 4a4f4f78cb [RISCV] Add test cases to show missed opportunities to use fnmadd/fnmsub if the second operand to the fma is negated rather than the first. NFC
We need to add more isel patterns to handle this.
2020-11-05 14:00:25 -08:00
Roger Ferrer Ibanez 3c24aee7ee [RISCV] Select +0.0 immediate using fmv.{w,d}.x / fcvt.d.w
Floating point positive zero can be selected using fmv.w.x / fmv.d.x /
fcvt.d.w and the zero source register.

Differential Revision: https://reviews.llvm.org/D75729
2020-03-20 09:42:24 +00:00
Luis Marques 3d0fbafd0b [RISCV] Switch to the Machine Scheduler
Most of the test changes are trivial instruction reorderings and differing
register allocations, without any obvious performance impact.

Differential Revision: https://reviews.llvm.org/D66973

llvm-svn: 372106
2019-09-17 11:15:35 +00:00
Luis Marques 2d550d19b3 Revert Patch from Phabricator
This reverts r372092 (git commit e38695a025)

llvm-svn: 372104
2019-09-17 10:52:09 +00:00
Luis Marques e38695a025 Patch from Phabricator
llvm-svn: 372092
2019-09-17 09:43:08 +00:00
Alex Bradbury d834d8301d [RISCV] Add RV64F codegen support
This requires a little extra work due tothe fact i32 is not a legal type. When
call lowering happens post-legalisation (e.g. when an intrinsic was inserted
during legalisation). A bitcast from f32 to i32 can't be introduced. This is
similar to the challenges with RV32D. To handle this, we introduce
target-specific DAG nodes that perform bitcast+anyext for f32->i64 and
trunc+bitcast for i64->f32.

Differential Revision: https://reviews.llvm.org/D53235

llvm-svn: 352807
2019-01-31 22:48:38 +00:00
Alex Bradbury 38c4ec31cb [RISCV] Add tests to demonstrate bitcasted fneg/fabs dagcombines
This target-independent code won't trigger for cases such as RV32FD where
custom SelectionDAG nodes are generated. These new tests demonstrate such
cases. Additionally, float-arith.ll was updated so that fneg.s, fsgnjn.s, and
fabs.s selection patterns are actually exercised.

llvm-svn: 352199
2019-01-25 14:33:08 +00:00
Alex Bradbury 919f5fb8ca [RISCV] Add support for the various RISC-V FMA instruction variants
Adds support for the various RISC-V FMA instructions (fmadd, fmsub, fnmsub, fnmadd).

The criteria for choosing whether a fused add or subtract is used, as well as
whether the product is negated or not, is whether some of the arguments to the
llvm.fma.* intrinsic are negated or not. In the tests, extraneous fadd
instructions were added to avoid the negation being performed using a xor
trick, which prevented the proper FMA forms from being selected and thus
tested.

The FMA instruction patterns might seem incorrect (e.g., fnmadd: -rs1 * rs2 -
rs3), but they should be correct. The misleading names were inherited from
MIPS, where the negation happens after computing the sum.

The llvm.fmuladd.* intrinsics still do not generate RISC-V FMA instructions,
as that depends on TargetLowering::isFMAFasterthanFMulAndFAdd.

Some comments in the test files about what type of instructions are there
tested were updated, to better reflect the current content of those test
files.

Differential Revision: https://reviews.llvm.org/D54205
Patch by Luís Marques.

llvm-svn: 349023
2018-12-13 10:49:05 +00:00
Alex Bradbury 3ff2022bb9 [RISCV] Introduce pattern for materialising immediates with 0 for lower 12 bits
These immediates can be materialised with just an lui, rather than an lui+addi 
pair.

llvm-svn: 330293
2018-04-18 20:34:23 +00:00
Alex Bradbury 099c720426 Revert "[RISCV] implement li pseudo instruction"
Reverts rL330224, while issues with the C extension and missed common
subexpression elimination opportunities are addressed. Neither of these issues
are visible in current RISC-V backend unit tests, which clearly need
expanding.

llvm-svn: 330281
2018-04-18 19:02:31 +00:00
Alex Bradbury 480b7bc906 [RISCV] implement li pseudo instruction
The implementation follows the MIPS backend and expands the
pseudo instruction directly during asm parsing. As the result, only
real MC instructions are emitted to the MCStreamer. Additionally,
PseudoLI instructions are emitted during codegen. The actual
expansion to real instructions is performed during MI to MC lowering
and is similar to the expansion performed by the GNU Assembler.

Differential Revision: https://reviews.llvm.org/D41949
Patch by Mario Werner.

llvm-svn: 330224
2018-04-17 21:56:40 +00:00
Alex Bradbury 76c29ee815 [RISCV] Add codegen for RV32F arithmetic and conversion operations
Currently, only a soft floating point ABI is supported.

llvm-svn: 327976
2018-03-20 12:45:35 +00:00